This little tool is awesome to refill a DCT / UDCT Cartomizer Tank. It makes the process of refilling the tank super easy, no more spills and awkward positioning to get liquid in there, almost all the way to the top. The quality it top notch, it's a perfect fit, and the rubber seal, much like that of a drip tip fits perfectly to the opening of the cartomizer. $4 for a little machined tool, but worth every penny. Available at Vapingzone, I have not come across it elsewhere to date.